Lycium chinense is acknowledged for its substantial nutritional benefits, particularly attributed to the high levels of ascorbic acid (AsA) found in its fruits. The “Mengqi No.1” variety of L. chinense, which is cultivated in Qinghai, is known for its high yield and exceptional quality. We utilized the “Mengqi No.1” variety as experimental materials and combined metabolomic, transcriptomic, and physiological analyses to investigate the metabolites, genes, and enzymes related to AsA metabolism in L. chinense fruits. The results revealed nine differential metabolites associated with AsA metabolism in L. chinense fruits across three stages, including 1D-Myo-Inositol-1,4-Bisphosphate, D-Fructose, L-(+)-Arabinose, I-Inositol, L-Arabinitol, D-Galactose-1-P, lactose, α-D-Glucose, and D-Glucose-6-P. Notably, the contents of D-Glucose-6-P, D-Galactose-1-P, and D-Fructose were increased as the fruit developed. Additionally, fresh weight, longitudinal length, and radial width were increased, while the contents of AsA and DHA were decreased. GalDH and DHAR are critical enzymes for the accumulation of AsA and DHA, exhibiting positive correlation coefficient. Furthermore, PMM1, PMM5, GME2, and GME3 were identified as key regulatory genes in the L-Galactose pathway of AsA synthesis, influencing D-Galactose-1-P, D-Glucose-6-P, α-D-Glucose, and D-Fructose. DHAR1 and DHAR2 are considered key positive regulator genes of AsA and DHA in the AsA-GSH cycle. However, the majority of genes (nine) act as negative regulators of AsA and DHA. These findings provide a foundation for the understanding of the regulatory mechanism of AsA metabolism in L. chinense fruits and offer insights into the utilization of AsA from L. chinense.

Phlomoides rotata, a traditional medicinal plant, always grows on the Tibetan Plateau at a high altitude of 3100–5200 m. The major active ingredients in P. rotata were used in medicines due to their diverse pharmacological effects, including hemostatic, anti-inflammatory, antitumor, immuno-modulatory, and antioxidant activities. This study screened 15 top endophytic genus through the analysis of OTUs and the top 30 metabolites with relatively high content in P. rotata roots from four different habitats (HN, GL, YS, and CD regions) in Qinghai Province. Twelve physicochemical indicators were measured and analyzed in the rhizosphere soils of P. rotata habitats. The results indicated that the top 30 metabolites compounds included 7 amino acids, 5 sugars and alcohols, 4 phenylpropanoids, 3 Organic acids, and 3 Alkaloids. Four endophytic bacteria (Acidibacter, Sphingomonas, Variovorax, and Sphingobium) and three endophytic fungi (Tetracladium, Cadophora, and Minimelanolocus) were dominant genera in P. rotata roots from four habitats. There were 109 positive significant correlations and 57 negative correlations between OTUs of endophytic bacteria and contents of top 30 metabolites, and 59 positive significant correlations and 58 negative correlations between OTUs of endophytic fungus and contents of top 30 metabolites. The OTUs of Acidibacter were significantly positively correlated with the content of 5 soil physicochemical indicators (total phosphorus, amylase, sucrase, total potassium, or soil organic carbon) and significantly negatively correlated with the content of acid protease. OTUs of Tetracladium or Cadophora showed a positive correlation with the content of total phosphorus and a negative correlation with that of alkaline phosphatase. This study provides a theoretical basis for the study of the correlation between endophytes and metabolites in P. rotata roots.

Phlomoides rotata, a traditional medicinal plant, is commonly found on the Tibetan Plateau at altitudes of 3100–5200 m. Its primary active medicinal compounds, flavonoids and phenylethanol glycosides (PhGs), exhibit various pharmacological effects, including hemostatic, anti-inflammatory, antitumor, immunomodulatory, and antioxidant activities. This study analyzed flavonoid and PhG metabolites in the roots of P. rotata collected from Henan County (HN), Guoluo County (GL), Yushu County (YS), and Chengduo County (CD) in Qinghai Province. A total of differentially abundant metabolites (DAMs) including 38 flavonoids and 21 PhGs were identified. Six genes (UFGT1, CHS1, COMT2, C4H3, C4H8, and C4H5) and four enzymes (4CL, C4H, PPO, and ALDH) were found to play key roles in regulating flavonoid and PhG biosynthesis in P. rotata roots. With increasing altitude, the relative content of 15 metabolites, the expression of seven genes, and the activity of four enzymes associated with flavonoid and PhG metabolism increased. These findings enhance our understanding of the regulatory mechanisms of flavonoid and PhG metabolism in P. rotata and provide insights into the potential pharmaceutical applications of its bioactive compounds.

Background: Lycium chinense has been acknowledged for its substantial nutritional benefits. The “Mengqi No.1” variety of L. chinense is known for its high yield and exceptional quality. Methods: We screened twenty dominant endophytic bacterial genera based on OTUs from L. chinense fruits during three developmental stages. Results: Forty-three differential amino acid metabolites were selected from L. chinense fruits. Five endophytic bacteria (Enterococcus, Escherichia-Shigella, Bacteroides, Pseudomonas, and Bacillus) were dominant genera in green fruit (GF, 16–19 days after flowering), color-changing fruit (CCF, 22–25 days after flowering), and red-ripe fruit (RRF, 31–34 days after flowering). Four endophytic bacterial genera (Enterococcus, Bacillus, Pseudomonas, and Rhodanobacter) showed positive correlation with twenty different amino acid metabolites and negative correlation with seven different amino acid metabolites. Conclusions: Five genes (AST1, ltaE1, TAT1, SHMT2, and SHMT3) indicated positive correlation with seventeen different amino acid metabolites and negative correlation with eight different amino acid metabolites. AST1 gene had a major role in regulating arginine biosynthesis (ko00220); ltaE1, SHMT2, and SHMT3 genes were major in regulating glycine, serine, and threonine metabolism (ko00260); and TAT1 gene had a major role in regulating tyrosine metabolism (ko00350). These findings offer insights into the relationship between amino acid synthesis and endophytic bacteria in L. chinense fruits.